An 82-year-old man was referred for endoscopic ultrasound of an ulcerated subepithelial mass in the duodenal sweep. The mass was initially identified during upper endoscopy for coffee-ground emesis. During endoscopic ultrasound, a 21-mm hypoechoic ulcerated subepithelial mass with a duct-like structure was identified. During suction to appose the lesion against the tip of the echoendoscope, the ulceration opened into a fistulous tract with drainage of bile and stones. Subsequent abdominal imaging demonstrated that the mass-like duodenal lesion abutted the gallbladder, which had an air-fluid level. We report a cholecystoenteric fistula masquerading as a subepithelial duodenal mass.